On the eve of the Windows Hardware Engineering Conference (WinHEC) 2004 trade show, Microsoft announced a sweeping set of changes to its Digital Rights Management (DRM) technology that will let online services provide subscription-based content. The technology, which is code-named Janus, will let online music stores and other e-commerce sites offer music, videos, and other digital-media content on a subscription basis rather than for purchase. Users can then transfer the content to portable audio and video devices. When the subscription lapses, the content stops playing on the devices, Microsoft said. 
  
"At the moment, the current subscription models that are out there are hobbled by the fact that they cannot be taken away from the computer," a Microsoft spokesperson said. Device makers are prepping new devices for release in the next 2 to 3 months that will take advantage of the technology.
  
Janus will further differentiate Windows Media-based online music stores from standard purchase-oriented stores such as the Apple iTunes Music Store. Companies such as AOL, Napster, and The Walt Disney Company will implement Janus in future online services, Microsoft said.